Ectopic Survivin purifies with the mitochondrial fraction and prevents FKHRL1-induced cell death at the level of mitochondria. (A) Mitochondrial activity was assessed by CMX-Ros staining in untreated and 4OHT-treated (75 nM, 48 h) SH-EP/FKHRL1-Ctr and SH-EP/FKHRL1-Surv cells. (B) Cytosolic and mitochondrial extracts of either untreated or 75 nM 4OHT-treated SH-EP/FKHRL1-Ctr and SH-EP/FKHRL1-Surv cells were prepared after 8 h (top) and 24 h (bottom) and analyzed for the expression of Survivin, cytochrome c, Cox4, BAX, and Bim. α-Tubulin (cytosolic) and Cox4 (mitochondrial) served as markers for the purity of subcellular fractions.